Many electronic devices utilize field effect transistors for amplifiers. heterojunction field effect transistors (HFETs) have been used for high frequency amplifiers, such as for microwave transmissions. As wider bandwidth signals of greater complexity are transmitted, larger bandwidth of greater complexity are transmitted, larger bandwidth amplifiers are required to transmit them. The most common approach to broad bandwidth is to take a high power narrow band amplifier design and make it broadband by sacrificing power for bandwidth. The only way to boost the broadband power back to narrowband levels is to use a higher power amplifier transistor. GaN is a desired choice for higher microwave power transistors. GaAs transistors have also been used to less extent. GaN is a fundamentally higher power choice because it is larger bandgap which permits higher voltage operation, and higher temperature operation than GaAs. It is also more chemically stable than GaAs which gives it advantages in reliability.
Beyond high power amplifiers, there is a need for GaN receiver transistors because they can survive unintentional exposure to high voltages. For example, if something passes directly in front of a transmitting radar, the reflected beam back to the radar receiver can burn out the receiver front-end transistor.